Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS) V. 膨胀超海王星 WASP-166b 上的钠探测
Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS) V. Detection of sodium on the bloated super-Neptune WASP-166b
J. V. Seidel, D. Ehrenreich, V. Bourrier, R. Allart, M. Attia, H. J. Hoeijmakers, M. Lendl, E. Linder, A. Wyttenbach, N. Astudillo-Defru, D. Bayliss, H. M. Cegl… 展开作者
J. V. Seidel, D. Ehrenreich, V. Bourrier, R. Allart, M. Attia, H. J. Hoeijmakers, M. Lendl, E. Linder, A. Wyttenbach, N. Astudillo-Defru, D. Bayliss, H. M. Cegla, Kevin Heng, B. Lavie, C. Lovis, C. Melo, F. Pepe, L. A. dos Santos, D. Ségransan, S. Udry
备注：
7 pages, 7 figures, accepted for publication in A&A
Planet formation processes or evolution mechanisms are surmised to be at the origin of the hot Neptune desert. Studying exoplanets currently living within or at the edge of this desert could allow disentangling the respective roles of formation and evolution. We present the HARPS transmission spectrum of the bloated super-Neptune WASP-166b, located at the outer rim of the Neptune desert. Neutral sodium is detected at the 3.4 $σ$ level ($0.455 \pm 0.135 %$), with a tentative indication of line broadening, which could be caused by winds blowing sodium farther into space, a possible manifestation of the bloated character of these highly irradiated worlds. We put this detection into context with previous work claiming a non-detection of sodium in the same observations and show that the high noise in the trace of the discarded stellar sodium lines was responsible for the non-detection. We highlight the impact of this low signal-to-noise remnant on detections for exoplanets similar to WASP-166b.
We report three new transiting hot-Jupiter planets discovered from the WASP surveys combined with radial velocities from OHP/SOPHIE and Euler/CORALIE and photometry from Euler and TRAPPIST. All three planets are inflated, with radii 1.7-1.8 Rjup. All orbit hot stars, F5-F7, and all three stars have evolved, post-MS radii (1.7-2.2 Rsun). Thus the three planets, with orbits of 1.8-3.9 d, are among the most irradiated planets known. This reinforces the correlation between inflated planets and stellar irradiation.
We report the discovery of WASP-166b, a super-Neptune planet with a mass of 0.1 Mjup (1.9 Mnep) and a bloated radius of 0.63 Rjup. It transits a V = 9.36, F9V star in a 5.44-d orbit that is aligned with the stellar rotation axis (sky-projected obliquity angle lambda = 3 +/- 5 degrees). Variations in the radial-velocity measurements are likely the result of magnetic activity over a 12-d stellar rotation period. WASP-166b appears to be a rare object within the ``Neptune desert''.
We report the discovery of WASP-78b and WASP-79b, two highly-bloated Jupiter-mass exoplanets orbiting F-type host stars. WASP-78b orbits its V=12.0 host star (TYC 5889-271-1) every 2.175 days and WASP-79b orbits its V=10.1 host star (CD-30 1812) every 3.662 days. Planetary parameters have been determined using a simultaneous fit to WASP and TRAPPIST transit photometry and CORALIE radial-velocity measurements. For WASP-78b a planetary mass of 0.89 +/- 0.08 M_Jup and a radius of 1.70 +/- 0.11 R_Jup is found. The planetary equilibrium temperature of T_P = 2350 +/- 80 K for WASP-78b makes it one o…
We present the discovery of four new giant planets from \WASP, three hot Jupiters and one bloated sub-Saturn mass planet; WASP-169b, WASP-171b, WASP-175b and WASP-182b. Besides the discovery photometry from \wasp\ we use radial velocity measurements from CORALIE and HARPS as well as follow-up photometry from EulerCam, TRAPPIST-North and -South and SPECULOOS. WASP-169b is a low density Jupiter ($M=0.561 \pm 0.061~\mathrm{M_{Jup}}, R=1.304^{+0.150}_{-0.073} ~\mathrm{R_{Jup}}$) orbiting a V=12.17 F8 sub-giant in a 5.611~day orbit. WASP-171b is a typical hot Jupiter ($M=1.084 \pm 0.094~\mathrm{M_{…
We present photometry of two transits of the giant planet WASP-4b with a photometric precision of 400-800 parts per million and a time sampling of 25-40 seconds. The two midtransit times are determined to within 6 seconds. Together with previously published times, the data are consistent with a constant orbital period, giving no compelling evidence for period variations that would be produced by a satellite or additional planets. Analysis of the new photometry, in combination with stellar-evolutionary modeling, gives a planetary mass and radius of 1.237 +/- 0.064 M_jup and 1.365 +/- 0.021 R_ju…
We present the detection of sodium absorption in the atmosphere of the extrasolar planet WASP-17b, an inflated 'hot-Jupiter' in a tight orbit around an F6 dwarf. In-transit observations of WASP-17 made with the MIKE spectrograph on the 6.5-m Magellan Telescope were analysed for excess planetary atmospheric absorption in the sodium I 'D' doublet spectral region. Using the interstellar sodium absorption lines as reference, we detect an excess 0.58 \pm 0.13 per cent transit signal, with 4.5σ confidence, at 1.5 Å bandwidth around the stellar sodium absorption feature. This result is consistent wit…
WASP-127b is one of the puffiest exoplanets found to date, with a mass only $3.4$ Neptune masses, but a radius larger than Jupiter. It is also located at the border of the Neptune desert, which describes the lack of highly-irradiated Neptune-sized planets, and which remains poorly understood. Its large scale height and bright host star make the transiting WASP-127b a valuable target to characterise in transmission spectroscopy. We use combined EulerCam and TESS light curves to recalculate the system's parameters. Additionally, we present an in-depth search for sodium in four transit observatio…
We report the discovery by the WASP transit survey of a highly-irradiated, massive (2.242 +/- 0.080 MJup) planet which transits a bright (V = 10.6), evolved F8 star every 2.9 days. The planet, WASP-71b, is larger than Jupiter (1.46 +/- 0.13 RJup), but less dense (0.71 +/- 0.16 ρJup). We also report spectroscopic observations made during transit with the CORALIE spectrograph, which allow us to make a highly-significant detection of the Rossiter-McLaughlin effect. We determine the sky-projected angle between the stellar-spin and planetary-orbit axes to be λ = 20.1 +/- 9.7 degrees, i.e. the syste…
We report the first detection of sodium absorption in the atmosphere of the hot Jupiter WASP-52b. We observed one transit of WASP-52b with the low-resolution Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy (OSIRIS) at the 10.4 m Gran Telescopio Canarias (GTC). The resulting transmission spectrum, covering the wavelength range from 522 nm to 903 nm, is flat and featureless, except for the significant narrow absorption signature at the sodium doublet, which can be explained by an atmosphere in solar composition with clouds at 1 mbar. A cloud-free atmosphere is …
We report the discovery of two transiting planetary systems: a super dense, sub-Jupiter mass planet WASP-86b (\mpl\ = 0.82 $\pm$ 0.06 \mj, \rpl\ = 0.63 $\pm$ 0.01 \rj), and a bloated, Saturn-like planet WASP-102b (\mpl\ = 0.62 $\pm$ 0.04 \mj, \rpl\=1.27 $\pm$ 0.03 \rj). They orbit their host star every $\sim$5.03, and $\sim$2.71 days, respectively. The planet hosting WASP-86 is a F7 star (\teff\ = 6330$\pm$110 K, \feh\ = $+$0.23 $\pm$ 0.14 dex, and age $\sim$0.8--1~Gyr), WASP-102 is a G0 star (\teff\ = 5940$\pm$140 K, \feh\ = $-$0.09$\pm$ 0.19 dex, and age $\sim$1~Gyr). These two systems highl…
We report the discovery of eight hot-Jupiter exoplanets from the WASP-South transit survey. WASP-144b has a mass of 0.44 Mj, a radius of 0.85 Rj, and is in a 2.27-d orbit around a V = 12.9, K2 star which shows a 21-d rotational modulation. WASP-145Ab is a 0.89 Mj planet in a 1.77-d orbit with a grazing transit, which means that the planetary radius is not well constrained. The host is a V = 11.5, K2 star with a companion 5 arcsecs away and 1.4 mags fainter. WASP-158b is a relatively massive planet at 2.8 Mj with a radius of 1.1 Rj and a 3.66-d orbit. It transits a V = 12.1, F6 star. WASP-159b …
The hot Neptune desert, a distinct lack of highly irradiated planets in the size range of Neptune, remains one of the most intriguing results of exoplanet population studies. A deeper understanding of the atmosphere of exoplanets sitting at the edge or even within the Neptune desert will allow us to better understand if planetary formation or evolution processes are at the origin of the desert. A detection of sodium in WASP-166b was presented previously with tentative line broadening at the 3.4 sigma with the HARPS spectrograph. We update this result with two transits observed with the ESPRESS…
Motivated by both ground- and space-based detections of the sodium doublet in the transmission spectra of exoplanetary atmospheres, we revisit the theory and interpretation of sodium lines in non-local thermodynamic equilibrium (NLTE), where collisions are not efficient enough to maintain a Boltzmann distribution for the excited and ground states of the sodium atom. We consider non-Boltzmann distributions that account for the ineffectiveness of collisions. We analyze the sodium doublet in transmission spectra measured at low (HAT-P-1b, HAT-P-12b, HD 189733b, WASP-6b, WASP-17b and WASP-39b) and…
High-resolution optical spectroscopy during the transit of HD 189733b, a prototypical hot Jupiter, allowed the resolution of the Na I D sodium lines in the planet, giving access to the extreme conditions of the planet upper atmosphere. We have undertaken HEARTS, a spectroscopic survey of exoplanet upper atmospheres, to perform a comparative study of hot gas giants and determine how stellar irradiation affect them. Here, we report on the first HEARTS observations of the hot Saturn-mass planet WASP-49b. We observed the planet with the HARPS high-resolution spectrograph at ESO 3.6m telescope. We …
High-resolution optical spectroscopy is a powerful tool to characterise exoplanetary atmospheres from the ground. The sodium D lines, with their large cross sections, are especially suited to study the upper layers of atmospheres in this context. We report on the results from HEARTS, a spectroscopic survey of exoplanet atmospheres, performing a comparative study of hot gas giants to determine the effects of stellar irradiation. In this second installation of the series, we highlight the detection of neutral sodium on the ultra-hot giant WASP-76b. We observed three transits of the planet using …
We present an optical transmission spectrum for WASP-94A b, the first atmospheric characterisation of this highly-inflated hot Jupiter. The planet has a reported radius of $1.72^{+0.06}_{-0.05}$ R$_{\textrm{Jup}}$, a mass of only $0.456^{+0.032}_{-0.036}$ M$_{\textrm{Jup}}$, and an equilibrium temperature of $1508 \pm 75$ K. We observed the planet transit spectroscopically with the EFOSC2 instrument on the ESO New Technology Telescope (NTT) at La Silla, Chile: the first use of NTT/EFOSC2 for transmission spectroscopy. We achieved an average transit-depth precision of $128$ ppm for bin widths o…
We present the optical transmission spectrum of the highly inflated Saturn-mass exoplanet WASP-21b, using three transits obtained with the ACAM instrument on the William Herschel Telescope through the LRG-BEASTS survey (Low Resolution Ground-Based Exoplanet Atmosphere Survey using Transmission Spectroscopy). Our transmission spectrum covers a wavelength range of 4635-9000 Angstrom, achieving an average transit depth precision of 197ppm compared to one atmospheric scale height at 246ppm. We detect Na I absorption in a bin width of 30 Angstrom, at >4$σ$ confidence, which extends over 100 Angstro…
We have obtained $> 10$ hours of medium resolution ($R \sim 15000$) spectroscopic exposures on the transiting exoplanet host star WASP-12, including $\sim2$ hours while its planet, WASP-12b, is in transit, with the Hobby-Eberly Telescope (HET). The out-of-transit and in-transit spectra are coadded into master out-of-transit and in-transit spectra, from which we create a master transmission spectrum. Strong, statistically significant absorption features are seen in the transmission spectrum at H$α$ and \ion{Na}{1} (the Na D doublet). There is the suggestion of pre- and post-transit absorption i…
The technique of transmission spectroscopy allows us to constrain the chemical composition of the atmospheres of transiting exoplanets. It relies on very high signal-to-noise spectroscopic (or spectrophotometric) observations and is thus most suited for bright exoplanet host stars. In the era of TESS, NGST and PLATO, more and more suitable targets, even for mid-sized telescopes, are discovered. Furthermore, a wealth of archival data is available that could become a basis for long-term monitoring of exo-atmospheres. We analyzed archival HARPS spectroscopic time series of four host stars to tran…
We report the measurement of a spin-orbit misalignment for WASP-79b, a recently discovered, bloated transiting hot Jupiter from the WASP survey. Data were obtained using the CYCLOPS2 optical-fiber bundle and its simultaneous calibration system feeding the UCLES spectrograph on the Anglo-Australian Telescope. We have used the Rossiter-McLaughlin effect to determine the sky-projected spin-orbit angle to be lambda = -106+19-13 degrees. This result indicates a significant misalignment between the spin axis of the host star and the orbital plane of the planet -- the planet being in a nearly polar o…
The detection of increased sodium absorption during primary transit implies the presence of an atmosphere around an extrasolar planet, and enables us to infer the structure of this atmosphere. Sodium has only been detected in the atmospheres of two planets to date - HD189733b and HD209458b. WASP-17b is the least dense planet currently known. It has a radius approximately twice that of Jupiter and orbits an F6-type star. The transit signal is expected to be about five times larger than that observed in HD209458b. We obtained 24 spectra with the GIRAFFE spectrograph on the VLT, eight during tran…
High-resolution transmission spectroscopy is a method for understanding the chemical and physical properties of upper exoplanetary atmospheres. Due to large absorption cross-sections, resonance lines of atomic sodium D-lines (at 5889.95 $Å$ and 5895.92 $Å$) produce large transmission signals. Our aim is to unveil the physical properties of WASP-17b through an accurate measurement of the sodium absorption in the transmission spectrum. We analyze 37 high-resolution spectra observed during a single transit of WASP-17b with the MIKE instrument on the 6.5 meter Magellan Telescopes. We exclude stell…
We report on four new transiting hot Jupiters discovered by the WASP-South survey. WASP-178b transits a V = 9.9, A1V star with Teff = 9350 +/- 150 K, the second-hottest transit host known. It has a highly bloated radius of 1.81 +/- 0.09 Rjup, in line with the known correlation between high irradiation and large size. With an estimated temperature of 2470 +/- 60 K, the planet is one of the best targets for studying ultra-hot Jupiters that is visible from the Southern hemisphere. The three host stars WASP-184, WASP-185 and WASP-192 are all post-main-sequence G0 stars of ages 4-8 Gyr. The larger …
Transit spectroscopy is one of the most commonly used methods to characterize exoplanets atmospheres. From the ground, these observations are very challenging due to the terrestrial atmosphere and its intrinsic variations, but high-spectral resolution observations overcome this difficulty by resolving the spectral lines and taking advantage of the different Doppler velocities of the Earth, the host star and the exoplanet. We analyze the transmission spectrum around the Na I doublet at 589 nm of the exoplanet WASP-69b, a hot Jupiter orbiting a K-type star with a period of 3.868 days, and compar…
We present transit photometry of three exoplanets, TrES-4b, HAT-P-3b, and WASP-12b, allowing for refined estimates of the systems' parameters. TrES-4b and WASP-12b were confirmed to be "bloated" planets, with radii of 1.706 +/- 0.056 R_Jup and 1.736 +/- 0.092 R_Jup, respectively. These planets are too large to be explained with standard models of gas giant planets. In contrast, HAT-P-3b has a radius of 0.827 +/- 0.055 R_Jup, smaller than a pure hydrogen-helium planet and indicative of a highly metal-enriched composition. Analyses of the transit timings revealed no significant departures from s…
We report measurements of the sky-projected spin--orbit angles for three transiting hot Jupiters: two of which are in nearly polar orbits, WASP-100b and WASP-109b, and a third in a low obliquity orbit, WASP-72b. We obtained these measurements by observing the Rossiter--McLaughlin effect over the course of the transits from high resolution spectroscopic observations made with the CYCLOPS2 optical fiber bundle system feeding the UCLES spectrograph on the Anglo-Australian Telescope. The resulting sky-projected spin--orbit angles are $λ= {-7^{\circ}}^{+11^{\circ}}_{-12^{\circ}}$, $λ= {79^{\circ}}^…
We present an atmospheric transmission spectrum of the ultra-hot Jupiter WASP-76 b by analyzing archival data obtained with the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope (HST). The dataset spans three transits, two with a wavelength coverage between 2900 and 5700 Armstrong, and the third one between 5250 and 10300 Armstrong. From the one-dimensional, time dependent spectra we constructed white and chromatic light curves, the latter with typical integration band widths of ~200 Armstrong. We computed the wavelength dependent planet-to-star radii ratios takin…
We report the discovery of three new transiting hot Jupiters by WASP-South together with the TRAPPIST photometer and the Euler/CORALIE spectrograph. WASP-74b orbits a star of V = 9.7, making it one of the brighter systems accessible to Southern telescopes. It is a 0.95 M_Jup planet with a moderately bloated radius of 1.5 R_Jup in a 2-d orbit around a slightly evolved F9 star. WASP-83b is a Saturn-mass planet at 0.3 M_Jup with a radius of 1.0 R_Jup. It is in a 5-d orbit around a fainter (V = 12.9) G8 star. WASP-89b is a 6 M_Jup planet in a 3-d orbit with an eccentricity of e = 0.2. It is thus s…
We describe seven exoplanets transiting stars of brightness V = 10.1 to 12.4. WASP-130b is a "warm Jupiter" having an orbital period of 11.6 d around a metal-rich G6 star. Its mass and radius (1.23 +/- 0.04 Mjup; 0.89 +/- 0.03 Rjup) support the trend that warm Jupiters have smaller radii than hot Jupiters. WASP-131b is a bloated Saturn-mass planet (0.27 Mjup; 1.22 Rjup). Its large scale height and bright (V = 10.1) host star make it a good target for atmospheric characterisation. WASP-132b (0.41 Mjup; 0.87 Rjup) is among the least irradiated and coolest of WASP planets, having a 7.1-d orbit ar…
The study of exoplanet atmospheres is essential to understand the formation, evolution and composition of exoplanets. The transmission spectroscopy technique is playing a significant role in this domain. In particular, the combination of state-of-the-art spectrographs at low- and high-spectral resolution is key to our understanding of atmospheric structure and composition. Two transits of the close-in sub Saturn-mass planet,WASP-127b, have been observed with ESPRESSO in the frame of the Guaranteed Time Observations Consortium. Transit observations allow us to study simultaneously the system ar…
We report on a pilot study of a novel observing technique, defocussed transmission spectroscopy, and its application to the study of exoplanet atmospheres using ground-based platforms. Similar to defocussed photometry, defocussed transmission spectroscopy has an added advantage over normal spectroscopy in that it reduces systematic errors due to flat-fielding, PSF variations, slit-jaw imperfections and other effects associated with ground-based observations. For one of the planetary systems studied, WASP-12b, we report a tentative detection of additional Na absorption of 0.12+/-0.03[+0.03]% du…
We present a dimensionless index that quantifies the degree of cloudiness of the atmosphere of a transiting exoplanet. Our cloudiness index is based on measuring the transit radii associated with the line center and wing of the sodium or potassium line. In deriving this index, we revisited the algebraic formulae for inferring the isothermal pressure scale height from transit measurements. We demonstrate that the formulae of Lecavelier et al. and Benneke & Seager are identical: the former is inferring the temperature while assuming a value for the mean molecular mass and the latter is inferring…
The transiting extrasolar planet WASP-12 b was found to be one of the most intensely irradiated exoplanets. It is unexpectedly bloated and is losing mass that may accrete into the host star. Our aim was to refine the parameters of this intriguing system and search for signs of transit timing variations. We gathered high-precision light curves for two transits of WASP-12 b. Assuming various limb-darkening laws, we generated best-fitting models and redetermined parameters of the system. Error estimates were derived by the prayer bead method and Monte Carlo simulations. System parameters obtained…
We report the discovery of the transiting exoplanets WASP-69b, WASP-70Ab and WASP-84b, each of which orbits a bright star ($V\sim10)$. WASP-69b is a bloated Saturn-mass planet (0.26 $M_{\rm Jup}$, 1.06 $R_{\rm Jup}$) in a 3.868-d period around an active, $\sim$1-Gyr, mid-K dwarf. ROSAT detected X-rays $60 \pm 27"$ from WASP-69. If the star is the source then the planet could be undergoing mass-loss at a rate of $\sim$10$^{12}$ g s$^{-1}$. This is 1 to 2 orders of magnitude higher than the evaporation rate estimated for HD 209458b and HD 189733b, both of which have exhibited anomalously-large L…
We have performed ground-based transmission spectroscopy of the hot Jupiter orbiting the cool dwarf WASP-80 using the ACAM instrument on the William Herschel Telescope (WHT) as part of the LRG-BEASTS programme. This is the third paper of a ground-based transmission spectroscopy survey of hot Jupiters using low-resolution grism spectrographs. We observed two transits of the planet and have constructed transmission spectra spanning a wavelength range of 4640-8840A. Our transmission spectrum is inconsistent with a previously claimed detection of potassium in WASP-80b's atmosphere, and is instead …
A Comprehensive Analysis of the Panchromatic Transmission Spectrum of the Hot-Saturn WASP-96 b: Nondetection of Haze, Possible Sodium Limb Asymmetry, Stellar Characterization, and Formation History
We present transmission spectroscopy of the warm Saturn-mass exoplanet WASP-39b made with the Very Large Telescope (VLT) FOcal Reducer and Spectrograph (FORS2) across the wavelength range 411-810nm. The transit depth is measured with a typical precision of 240 parts per million (ppm) in wavelength bins of 10nm on a V = 12.1 magnitude star. We detect the sodium absorption feature (3.2-sigma) and find evidence for potassium. The ground-based transmission spectrum is consistent with Hubble Space Telescope (HST) optical spectroscopy, strengthening the interpretation of WASP-39b having a largely cl…
The strong, nearly wavelength-independent absorption cross section of aerosols produces featureless exoplanet transmission spectra, limiting our ability to characterize their atmospheres. Here we show that even in the presence of featureless spectra, we can still characterize certain atmospheric properties. Specifically, we constrain the upper and lower pressure boundaries of aerosol layers, and present plausible composition candidates. We study the case of the bloated Saturn-mass planet WASP-49b, where near-infrared observations reveal a flat transmission spectrum between 0.7 and 1.0 {\micron…
With high-resolution spectroscopy we can study exoplanet atmospheres and learn about their chemical composition, temperature profiles, and presence of clouds and winds, mainly in hot, giant planets. State-of-the-art instrumentation is pushing these studies towards smaller exoplanets. Of special interest are the few planets in the 'Neptune desert', a lack of Neptune-size planets in close orbits around their hosts. Here, we assess the presence of water in one such planet, the bloated super-Neptune WASP-166 b, which orbits an F9-type star in a short orbit of 5.4 days. Despite its close-in orbit, …
We report transmission spectroscopy of the bloated hot Jupiter WASP-74b in the wavelength range from 4000 to 6200 Å. We observe two transit events with the Very Large Telescope FOcal Reducer and Spectrograph (VLT FORS2) and present a new method to measure the exoplanet transit depth as a function of wavelength. The new method removes the need for a reference star in correcting the spectroscopic light curves for the impact of atmospheric extinction. It also provides improved precision, compared to other techniques, reaching an average transit depth uncertainty of 211 ppm for a solar-type star o…
Transmission spectroscopy is a prime technique to study the chemical composition and structure of exoplanetary atmospheres. Strong excess absorption signals have been detected in the optical Na I D1, 2 Fraunhofer lines during transits of hot Jupiters, which are attributed to the planetary atmospheres and allow us to constrain its structure. We study the atmosphere of WASP-7 b by means of high-resolution transit spectroscopy in the sodium lines. We analyzed a spectral transit time series of 89 high-resolution spectra of the hot Jupiter WASP-7 b that was observed using the Ultraviolet and Visual…
We present new analysis of infrared transmission spectroscopy of the cloud-free hot-Saturn WASP-96b performed with the Hubble and Spitzer Space Telescopes (HST and Spitzer). The WASP-96b spectrum exhibits the absorption feature from water in excellent agreement with synthetic spectra computed assuming a cloud-free atmosphere. The HST-Spitzer spectrum is coupled with Very Large Telescope (VLT) optical transmission spectroscopy which reveals the full pressure-broadened profile of the sodium absorption feature and enables the derivation of absolute abundances. We confirm and correct for a spectra…
Despite swift progress in the characterisation of exoplanet atmospheres in composition and structure, the study of atmospheric dynamics has not progressed at the same speed. While theoretical models have been developed to describe the lower layers of the atmosphere and, disconnected, the exosphere, little is known about the intermediate layers up to the thermosphere. We aim to provide a clearer picture of atmospheric dynamics for the class of ultra hot Jupiters, highly-irradiated gas giants, on the example of WASP-76~b. We analysed two datasets jointly, obtained with the HARPS and ESPRESSO spe…
We have measured the transmission spectrum of the extremely inflated hot Jupiter WASP-52b using simultaneous photometric observations in SDSS u', g' and a filter centred on the sodium doublet (NaI) with the ULTRACAM instrument mounted on the 4.2m William Herschel Telescope. We find that Rayleigh scattering is not the dominant source of opacity within the planetary atmosphere and find a transmission spectrum more consistent with wavelength-independent opacity such as from clouds. We detect an in-transit anomaly that we attribute to the presence of stellar activity and find that this feature can…
We present HST STIS optical transmission spectroscopy of the cool Saturn-mass exoplanet WASP-39b from 0.29-1.025 micron, along with complementary transit observations from Spitzer IRAC at 3.6 and 4.5 micron. The low density and large atmospheric pressure scale height ofWASP-39b make it particularly amenable to atmospheric characterization using this technique. We detect a Rayleigh scattering slope as well as sodium and potassium absorption features; this is the first exoplanet in which both alkali features are clearly detected with the extended wings predicted by cloud-free atmosphere models. …
Precise and frequent photometric follow-up studies of transit light curves are indispensable when accurately characterizing extrasolar planets. We present new multi-wavelength photometry of three transiting "Hot Jupiters", TrES-3b, WASP-2b and HAT-P-30b (WASP-51b). Data were acquired from an 0.8 meter telescope at Tarleton State University. When combined with literature data, allowed us to redetermine system parameters in a corresponding way. We developed GCX reduction pipeline and TAP, modeling and light curve fitting package to analyze the extracted light curves. We then used weighted mean r…
Broad absorption signatures from alkali metals, such as the sodium (Na I) and potassium (K I) resonance doublets, have long been predicted in the optical atmospheric spectra of cloud-free irradiated gas-giant exoplanets1,2,3. However, observations have only revealed the narrow cores of these features rather than the full pressure-broadened profiles4-6. Cloud and haze opacity at the day-night planetary terminator are considered responsible for obscuring the absorption-line wings, which hinders constraints on absolute atmospheric abundances7-9. Here we present an optical transmission spectrum fo…
Recent observations of the ultra-hot Jupiter WASP-76b have revealed a diversity of atmospheric species. Here we present new high-resolution transit spectroscopy of WASP-76b with GRACES at the Gemini North Observatory, serving as a baseline for the Large and Long Program "Exploring the Diversity of Exoplanet Atmospheres at High Spectral Resolution" (Exoplanets with Gemini Spectroscopy, or ExoGemS for short). With a broad spectral range of $400 - 1050$ nm, these observations allow us to search for a suite of atomic species. We recover absorption features due to neutral sodium (Na I), and report …
We present an optical to near-infrared transmission spectrum of the inflated hot Jupiter WASP-52b using three transit observations from the Space Telescope Imaging Spectrograph (STIS) mounted on the Hubble Space Telescope, combined with Spitzer/Infrared Array Camera (IRAC) photometry at 3.6 microns and 4.5 microns. Since WASP-52 is a moderately active (log(Lx/Lbol) = -4.7) star, we correct the transit light curves for the effect of stellar activity using ground-based photometric monitoring data from the All-Sky Automated Survey for Supernovae (ASAS-SN) and Tennessee State University's Automati…
We present new ground-based, multi-colour, broad-band photometric measurements of the physical parameters, transmission and emission spectra of the transiting extrasolar planet WASP-19b. The measurements are based on observations of 8 transits and four occultations using the 1.5m Danish Telescope, 14 transits at the PEST observatory, and 1 transit observed simultaneously through four optical and three near-infrared filters, using the GROND instrument on the ESO 2.2m telescope. We use these new data to measure refined physical parameters for the system. We find the planet to be more bloated and…
We present FORS2 (attached to ESO's Very Large Telescope) observations of the exoplanet WASP-17b during its primary transit, for the purpose of differential spectrophotometry analysis. We use the instrument in its Mask eXchange Unit (MXU) mode to simultaneously obtain low resolution spectra of the planet hosting star, as well as several reference stars in the field of view. The integration of these spectra within broadband and smaller 100$Å$ bins provides us with 'white' and spectrophotometric light curves, from 5700 to 8000$Å$. Through modelling the white light curve, we obtain refined bulk a…
